The present invention relates to a gearcase for transmitting motion with different speeds to at least two driving shafts for power devices in self-propelled farm machines.
Machines for use in the farming industry, specifically trailers towed by tractors for spreading forage, employ mechanisms that cause stored forage to slide on a platform of the trailer, gradually sending it toward one end of the trailer proximate to which a spreading unit is installed; the spreading unit is essentially constituted by one or more augers or scrolls having parallel and horizontal axes and which, by rotating, pick up the forage that arrives from the body and expel it outward.
In order to move said forage, the body has a conveyor belt constituted by a series of cross-members supported at their ends by motor-driven chains and move parallel to the bottom of the body so as to be flush with it.
Due to operating requirements, advancement of the conveyor belt and rotation of the scrolls must occur at different speeds.
This need is currently met from a technical standpoint by resorting to the use of a large number of gears which are mutually connected by chain-type transmissions coupled to said gears; for the sake of constructive simplicity and in order to accordingly contain production costs, said gears are arranged unprotected in regions of the machine which are close to the scroll connection and belt traction points.
This unprotected arrangement allows said gears, as well as all the mechanical components which cooperate with them in meeting the described technical requirement, to be easily damaged by external factors, such as bad weather and others.
Furthermore, the unavoidable need to contain costs has forced manufacturers to build the known devices in the simplest manner, depriving them of any synchronization device suitable to allow meshing and disengagement during the movement of the mechanisms suitable to provide overall movement, subjecting said gears to a very tough duty cycle and consequently requiring them to be oversized.